Engine generator apparatus and method of operating same

Abstract

When a motor/generator is changed over from a motor mode to a generator mode, field current is minimized. In the generator mode, idling is performed until the engine temperature attains a set temperature, after which the field current is supplied. As a result, load upon an engine is lightened immediately after the engine is started and the risk of the engine stalling is eliminated.

What is claimed is: 
     
       1. An engine generator apparatus having a motor/generator operated in a motor mode for starting an engine and in a generator mode to be driven by the engine, comprising: first control means for minimizing field current when a changeover is made from the motor mode to the generator mode;   second control means operable in the generator mode for maintaining rotational speed of the engine at a first set rotational speed until engine temperature attains a set temperature, and for outputting a signal, which increases the rotational speed of the engine to a second set rotational speed, to throttle-adjusting means after the engine temperature attains said set temperature; and   third control means for increasing the field current of the motor/generator from the minimum state after the engine temperature attains said set temperature.   
     
     
       2. The apparatus according to claim 1, wherein said third control means increases the field current after the rotational speed of the engine attains said second set rotational speed. 
     
     
       3. The apparatus according to claim 1, wherein temperature of engine coolant is used as the engine temperature. 
     
     
       4. The apparatus according to claim 1, wherein after the motor/generator is supplied with the field current in the generator mode, the field current is regulated by a signal indicative of output voltage and adjustment of throttle opening is performed based on a signal indicating the rotational speed of the engine. 
     
     
       5. The apparatus according to claim 1, further comprising external terminals for a remote starter switch and a voltmeter for output voltage. 
     
     
       6. The apparatus according to claim 1, wherein changeover from the motor mode to the generator mode is performed by mode changeover means comprising: a solenoid;   a disk driven by said solenoid;   a movable contact held by said disk; and   a set of fixed contacts for being engaged and disengaged by said movable contact.   
     
     
       7. The apparatus according to claim 1, wherein said first through third control means comprise a programmed computer. 
     
     
       8. The apparatus according to claim 1, wherein said engine generator apparatus is portable. 
     
     
       9. A generator/starter apparatus having a motor/generator operated in a motor mode for starting an engine and in a generator mode to be driven by the engine, comprising: first control means for minimizing field current when a changeover is made from the motor mode to the generator mode;   second control means operable in the generator mode for outputting, to throttle adjusting means, a signal for maintaining rotational speed of the engine at a first set rotational speed until engine temperature attains a set temperature, and for increasing the rotational speed of the engine to a second set rotational speed after the engine temperature attains the set temperature; and   third control means for increasing the field current of the motor/generator from the minimum state after the engine temperature attains said set temperature.   
     
     
       10. The apparatus according to claim 9, wherein said third control means increases the field current after the rotational speed of the engine attains said second set rotational speed. 
     
     
       11. The apparatus according to claim 9, wherein temperature of engine coolant is used as the engine temperature. 
     
     
       12. The apparatus according to claim 9, wherein after the motor/generator is supplied with the field current in the generator mode, the field current is regulated by a signal indicative of output voltage and a throttle opening adjustment signal is outputted based on a signal indicating the rotational speed of the engine. 
     
     
       13. The apparatus according to claim 9, wherein changeover from the motor mode to the generator mode is performed by mode changeover means comprising: a solenoid;   a disk driven by said solenoid;   a movable contact held by said disk; and   a set of fixed contacts for being engaged and disengaged by said movable contact.   
     
     
       14. The apparatus according to claim 9, wherein said first through third control means comprise a programmed computer. 
     
     
       15. The apparatus according to claim 9, wherein said generator/starter apparatus is a generator/starter apparatus for an automotive vehicle. 
     
     
       16. A method of operating a generator/starter apparatus having a motor/generator operated in a motor mode for starting an engine in a generator mode to a driven by the engine, comprising: a first step of effecting a changeover from the motor mode to the generator mode while minimizing field current;   a second step of outputting a signal for maintaining rotational speed of the engine at a predetermined set rotational speed until engine temperature attains a set temperature, and   a third step of increasing the field current of the motor/generator from the minimum state after the engine temperature attains said set temperature.   
     
     
       17. The method according to claim 16, wherein a step of increasing the rotational speed of the engine to a second set rotational speed after the engine temperature attains said set temperature is included ahead of said third step. 
     
     
       18. The method according to claim 16, wherein temperature of engine coolant is used as the engine temperature. 
     
     
       19. The method according to claim 16, wherein a step of adjusting field current by a signal indicative of output voltage and outputting a throttle opening adjustment signal based on the rotational speed of the motor/generator is included after said third step. 
     
     
       20. The method according to claim 16, wherein said first through third steps are effected by a programmed computer comprising the following steps: (a) comparing the rotational speed of the engine whether it is equal to or greater than a predetermined minimum rotational speed,   (b) if NO at step (a), outputting a signal indicative of the motor mode,   (c) if YES at step (a), outputting a signal minimizing the field current,   (d) comparing a signal indicative of the rotational speed of the engine whether it is equal to or greater than a first set rotational speed,   (e) if NO at step (d), outputting a signal indicative of setting the first set rotational speed,   (f) if YES at step (d), outputting a signal indicative of setting a second set rotational speed which is higher than the first set rotational speed.